This invention relates to an improved low pressure transducer that is sensitive to pressure differentials on the order of 1.5 to 5 inches of water but yet is quite rugged and inexpensive. More specifically, this invention relates to a low pressure transducer having a composite diaphragm comprised of an elastomeric barrier bonded to a stiff sensing element which serves as a backing for the elastomeric barrier and as a concentrator or collector of deflective force. The deflective force is concentrated in a narrow neck, which connects the sensing element to the transducer housing, where it is detected by strain gauges.
Prior to this invention, transducers capable of measuring very low pressures were generally fragile instruments because, at very low pressures, the energy available for transductance is very low, thus requiring a very sensitive instrument. Such fragile, sensitive instruments are difficult and expensive to build. Moreover, when working with very low pressures, the energy expended in deflecting a sensing barrier is quite high, leaving little to power the strain sensing element, and therefore giving an extremely low electrical output from the strain gauges.